Merge pull request #869 from 0xff-dev/2302

Add solution and test-cases for problem 2302

Author: 6boris

leetcode/2301-2400/2302.Count-Subarrays-With-Score-Less-Than-K/README.md

@@ -1,28 +1,39 @@
 # [2302.Count Subarrays With Score Less Than K][title]
 
-> [!WARNING|style:flat]
-> This question is temporarily unanswered if you have good ideas. Welcome to [Create Pull Request PR](https://github.com/kylesliu/awesome-golang-algorithm)
-
 ## Description
+The **score** of an array is defined as the **product** of its sum and its length.
+
+- For example, the score of `[1, 2, 3, 4, 5]` is `(1 + 2 + 3 + 4 + 5) * 5 = 75`.
+
+Given a positive integer array `nums` and an integer `k`, return the **number of non-empty subarrays** of `nums` whose score is **strictly less** than `k`.
+
+A **subarray** is a contiguous sequence of elements within an array.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: nums = [2,1,4,3,5], k = 10
+Output: 6
+Explanation:
+The 6 subarrays having scores less than 10 are:
+- [2] with score 2 * 1 = 2.
+- [1] with score 1 * 1 = 1.
+- [4] with score 4 * 1 = 4.
+- [3] with score 3 * 1 = 3. 
+- [5] with score 5 * 1 = 5.
+- [2,1] with score (2 + 1) * 2 = 6.
+Note that subarrays such as [1,4] and [4,3,5] are not considered because their scores are 10 and 36 respectively, while we need scores strictly less than 10.
 ```
 
-## 题意
-> ...
+**Example 2:**
 
-## 题解
-
-### 思路1
-> ...
-Count Subarrays With Score Less Than K
-```go
 ```
-
+Input: nums = [1,1,1], k = 5
+Output: 5
+Explanation:
+Every subarray except [1,1,1] has a score less than 5.
+[1,1,1] has a score (1 + 1 + 1) * 3 = 9, which is greater than 5.
+```
 
 ## 结语
 

leetcode/2301-2400/2302.Count-Subarrays-With-Score-Less-Than-K/Solution.go

@@ -1,5 +1,25 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+import "sort"
+
+func Solution(nums []int, k int64) int64 {
+	ans := int64(0)
+	for j := 1; j < len(nums); j++ {
+		nums[j] += nums[j-1]
+	}
+	for j := 0; j < len(nums); j++ {
+		l := j + 1
+		idx := sort.Search(l, func(i int) bool {
+			width := l - i
+			del := 0
+			if i > 0 {
+				del = nums[i-1]
+			}
+			return int64(nums[j]-del)*int64(width) < k
+		})
+		if idx != l {
+			ans += int64(l - idx)
+		}
+	}
+	return ans
 }

leetcode/2301-2400/2302.Count-Subarrays-With-Score-Less-Than-K/Solution_test.go

@@ -10,30 +10,30 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		nums   []int
+		k      int64
+		expect int64
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", []int{2, 1, 4, 3, 5}, 10, 6},
+		{"TestCase2", []int{1, 1, 1}, 5, 5},
 	}
 
 	//	开始测试
 	for i, c := range cases {
 		t.Run(c.name+" "+strconv.Itoa(i), func(t *testing.T) {
-			got := Solution(c.inputs)
+			got := Solution(c.nums, c.k)
 			if !reflect.DeepEqual(got, c.expect) {
-				t.Fatalf("expected: %v, but got: %v, with inputs: %v",
-					c.expect, got, c.inputs)
+				t.Fatalf("expected: %v, but got: %v, with inputs: %v %v",
+					c.expect, got, c.nums, c.k)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }